What happened with me was it only changed the name that is displayed above your head on my monitor (client side) but when I use map chat, normal chat, etc., the new name appears. So this is what happens:
Real name: "Alpha"
Fake name: "Beta"
Name displayed above the head client side: "Beta" (Fake name)
Name displayed above the head from other users' POV: "Alpha" (still the real name)
But when you use map chat, normal chat, etc.....:
Name displayed on chat box client side: "Beta" (fake name)
Name displayed on chat box from other users' POV: "Beta" (fake name)
Conclusion:
It Fails to change your displayed name above your head but i succeeds on changing your name when chatting.